F-19 MR imaging of glucose metabolism in the rabbit

Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging.     

Importance of measurement site on assessment of lesion-specific ischemia and diagnostic performance by coronary computed tomography Angiography-Derived Fractional Flow Reserve

BackgroundValues of fractional flow reserve (FFR_CT) by coronary computed tomography angiography (CTA) decline from the ostium to the terminal vessel, irrespective of stenosis severity. The purpose of this study is to determine if the site of measurement of FFR_CT impacts assessment of ischemia and its diagnostic performance relative to invasive FFR (FFR_INV).Methods1484 patients underwent FFR_CT; 1910 vessels were stratified by stenosis severity (normal; <25%, 25–50%, 50–70%, and >70% stenosis). The rates of positive FFR_CT (≤0.8) were determined by measuring FFR_CT from the terminal vessel and from distal-to-the-lesion. Reclassification rates from positive to negative FFR_CT were calculated. Diagnostic performance of FFR_CT relative to FFR_INV was evaluated in 182 vessels using linear regression, Bland Altman analysis, and receiver operating characteristic (ROC) curves.ResultsPositive FFR_CT was identified in 24.9% of vessels using terminal vessel FFR_CT and 10.1% using FFR_CT distal-to-the-lesion (p ?< ?0.001). FFR_CT obtained distal-to-the-lesion resulted in reclassification of 59.6% of positive terminal FFR_CT to negative FFR_CT. Relative to FFR_INV, there were improvements in specificity (50% to 86%, p ?< ?0.001), diagnostic accuracy (65% to 88%, p ?< ?0.001), positive predictive value (50% to 78%, p ?< ?0.001), and area-under-the-curve (AUC, 0.83 to 0.91, p ?< ?0.001) when FFR_CT was measured distal-to-the-lesion.ConclusionFFR_CT values from the terminal vessel should not be used to assess lesion-specific ischemia due to high rates of false positive results. FFR_CT measured distal-to-the-lesion improves the diagnostic performance of FFR_CT relative to FFR_INV, ensures that FFR_CT values are due to lesion-specific ischemia, and could reduce the rate of unnecessary invasive procedures.     

Factors linked to bacterial vaginosis in nonpregnant women

OBJECTIVES: The purposes of this study were to test the hypothesis that vaginal douching is linked to bacterial vaginosis in both symptomatic and asymptomatic women and to identify other demographic, reproductive, and lifestyle factors associated with bacterial vaginosis. METHODS: In this cross-sectional study involving 3 clinic sites, 496 nonpregnant women completed a self-administered questionnaire. Their vaginal smears were assessed and cross-validated for bacterial vaginosis. RESULTS: The prevalence of bacterial vaginosis across clinics ranged from 15% to 30%. In analyses restricted to site 1, adjusted odds ratios (ORs) for bacterial vaginosis remained significant for African American women with 13 or fewer years of education (OR = 5.5, 95% confidence interval [CI] = 2.1, 14.5), hormone use within the past 6 months (OR = 0.5, 95% CI = 0.2, 0.8), and vaginal douching within the past 2 months (OR = 2.9, 95% CI = 1.5, 5.6). CONCLUSIONS: Two lifestyle factors emerge as strongly associated with bacterial vaginosis: systemic contraceptives appear protective, whereas douching is linked to an increase in prevalence. The temporal relationship between douching and bacterial vaginosis needs further clarification.     

Digital beam attenuator technique for compensated chest radiography

The feasibility of producing patient-specific beam attenuators for chest radiography has been investigated using an anthropomorphic phantom and a human volunteer. A low-dose test exposure is digitized, processed, and used to print a small cerium filter, which is placed in the x-ray beam near the collimator. The final radiograph is recorded on film. The technique results in relatively uniform film exposure, so that structures in all regions of the chest are simultaneously displayed with optimal film contrast. The equalized exposure improves image quality in the normally underpenetrated regions and reduces the role of cross-scatter from the lungs. The image is analogous to optical or computer-processed unsharp masking techniques, but the processing is accomplished in the x-ray beam and results in an improved exposure distribution, giving advantages that cannot be achieved with image processing techniques alone.     

Simulated ABO and Rh blood typing

BACKGROUND: Blood typing historically has been used to introduce students to the concepts of immunohematology. Risk of disease transmission has compelled school districts to prohibit the use of human blood in student laboratories. A method is needed that will safely simulate ABO and Rh typing. STUDY DESIGN AND METHODS: A method that uses inorganic salt solutions to simulate ABO and Rh antigens and antibodies was studied. Additional salt solutions and diluents were tested to investigate the feasibility of simulating both ABO and Rh typing in a more realistic medium. RESULTS: Cobalt nitrate and sodium hydroxide were found to successfully simulate D and anti-D, respectively. The addition of these solutions did not produce cross- reactions in ABO tests. Use of simulated blood as a diluent improved the appearance of the samples. CONCLUSION: This method can safely and inexpensively simulate ABO and Rh blood typing procedures and provide students with hands-on blood-typing experience.     

Current autologous transfusion practices. Implications for the future

A questionnaire was distributed to 509 AABB institutional members to evaluate current autologous transfusion practices. Results were returned from 47 blood centers, 108 transfusion services and 64 hospital blood banks (response rate 43%). Results indicate that not all eligible patients are allowed to donate due to unnecessarily strict eligibility criteria. Thirty percent of autologous units are not tested for infectious disease markers. Of those units tested and found positive for anti-HIV or HBsAg, 53 and 72% respectively, of the institutions provide the units to the intended recipient. Forty-seven percent of institutions perform an AHG crossmatch for autologous recipients. Sixty five percent of institutions permit "crossing-over" of autologous units for homologous use. Implications of these findings for the development of standards for autologous transfusion programs are discussed.